Dipartimento di Scienze della Terra, Università degli studi Federico II, Largo San Marcellino 10, 80138 Napoli, Italy.
Proc Biol Sci. 2011 Dec 7;278(1724):3474-81. doi: 10.1098/rspb.2011.0273. Epub 2011 Apr 6.
The acquisition of hypsodont molars is often regarded as a key innovation in the history of ruminant ungulates. Hypsodont ruminants diversified rapidly during the later Neogene, circa 15-2 Myr ago, and came to dominate the ruminant fossil record in terms of species diversity. Here we show that hypsodont clades had higher speciation and diversification rates than other clades. Hypsodont species had, on average, shorter stratigraphic durations, smaller range size and lower occupancy than non-hypsodont species. Within hypsodont clades, some species were very common and acquired large geographical ranges, whereas others were quite rare and geographically limited. We argue that hypsodont clades diversified in an adaptive radiation-like fashion, with species often splitting cladogenetically while still in the expansive phase of their occupancy history.
获得高齿冠的磨牙通常被认为是反刍动物进化史上的一个关键创新。高齿冠反刍动物在大约 1500 万至 200 万年前的上新世后期迅速多样化，在物种多样性方面主导了反刍动物的化石记录。在这里，我们表明高齿冠进化枝的物种形成和多样化速率高于其他进化枝。高齿冠物种的地层持续时间平均更短，分布范围更小，占据度也低于非高齿冠物种。在高齿冠进化枝内，一些物种非常普遍，获得了广泛的地理分布范围，而其他物种则相当罕见，分布范围也有限。我们认为，高齿冠进化枝以类似于适应性辐射的方式多样化，物种在占据历史的扩张阶段往往会通过分支发生分裂。
